In recent years, according to the extensive spread of broadband of access networks in which an ADSL (Asymmetric Digital Subscriber Line), an FTTH (Fiber to The Home), and the like are used, a technique for performing communication using an IP (Internet Protocol) network called VoIP (Voice over IP) is developed.
On the other hand, the IETF (Internet Engineering Task Force), which is an Internet standardization organization, defines an SIP (Session Initiation Protocol). The SIP is a protocol that is being standardized as a technique for realizing real-time communication (e.g., IP telephone and video conference) on the IP network.
A facsimile apparatus is integrated with a telephone set. For example, a system for externally connecting the telephone set to the facsimile apparatus is adopted. A controller mounted on the facsimile apparatus determines an incoming signal and automatically switches a facsimile function and a telephone function.
Such a facsimile apparatus selects the facsimile function or the telephone function to perform exchange of a signal. Therefore, the facsimile apparatus may not be able to cause both the functions to simultaneously operate. In the facsimile apparatus connected to the IP telephone network to perform exchange of a signal according to the SIP, an interface function needs to be added between the facsimile apparatus and the telephone set, leading to an increase in costs.